The things that come out of the mouth are an overflow of the "abundance of the heart":
Soldier, be aware of the themes of your speech. Would a sensitive listener notice negativity?
Insecurity? Self-centeredness?
The heart and mind that is filled with and focused on God's Word is reflected by speech that encourages others.
Speech that builds up.
Speech that is about the Lord.
Speech that believes the best.
Speech that expresses faith.
Speech that puts others first.
His Word in your mouth.